Many people think that drinking tea is good, natural and healthy and has health benefits. So do you know exactly what ingredients make tea have these effects? What is EGCG that is often mentioned in the mouth of marketing? Today, let's take a comprehensive look at a large class of substances in the active ingredients of tea - tea polyphenols. If you're interested, read on
The polyphenols in tea are referred to as tea polyphenols, accounting for 18% to 36% of the dry matter of tea leaves, and in the early years of research, when the primary stage of research was also called "tea tannins" or "tea tannins", but these two names are now rarely used, saying polyphenols. What are the main contents of so many phenolic substances? Let's talk about them one by one.
I. Catechins
If you ask what substance in tea is the most famous? That is undoubtedly the EGCG in catechins, and there are many false propaganda about the efficacy of the anecdotes that like to talk about EGCG. The full name of the EGCG is "epigallocatechin gallate", and in the category of catechins, it has three other siblings, namely the ester catechin egeate ECG, and two simple catechins including epigechin EC and epigalcotean EGC.
Molecular structure of EGCG
Catechins are white solids, easily soluble in hot water, and prone to oxidation at high temperatures or under the action of oxidase. Embodied in the black tea production process, catechins will be oxidized to form theaflavins, further forming thearubicin, theaflamin, which has also been mentioned in the previous content.
Usually we mention that the antioxidant, antibacterial and antiviral effects of tea are mostly the functions of catechins.
2. Flavonoids, flavonoids
Flavonoids and flavonoids are mostly bright yellow crystals, of which flavonoids are difficult to dissolve in water, but flavonoids are soluble in water, and the aqueous solution is yellow-green, which has a greater effect on the formation of green tea soup color.
3. Anthocyanins, anthocyanins
Anthocyanins should be heard more, which are very common in plants and play a role in color. Like one of the tea varieties called "purple buds", its anthocyanin content will be much higher than that of ordinary tea buds. Anthocyanins, also known as "occult anthocyanins", are usually colorless and are oxidized into colored oxidation products during the fermentation process of black tea.
The main functions of both are antioxidant and scavenging free radicals, and can also be extracted and used as preservatives in food.
4. Phenolic acids and phenolic acids
The content of such substances in tea leaves is less, and it is astringent in tea soup, which enriches the taste of tea soup.
It can be seen that tea polyphenols not only have important physiological activities for the human body, but also are closely related to the quality of tea. Doesn't it say that the more polyphenols in all tea leaves, the better?
Not really. For example, the reason why summer and autumn tea is not as delicious as spring tea is precisely because the summer and autumn seasons have high temperatures and strong sunshine, the nitrogen metabolism level in the tea plant is relatively low, the polyphenols are higher, the amino acid substances are lower, the production of green tea is bitter and bitter, the quality is not as good as spring tea, and the price is naturally not as high as spring tea. Therefore, many colleges and universities are also doing research in this regard, wanting to reduce the bitterness of summer and autumn tea, reduce the content of phenolic substances, and enhance the product value of summer and autumn tea.
At present, in addition to the presence of tea polyphenols in tea leaves, tea polyphenol extracts are mainly used in food and daily chemical products, such as chewing gum, facial cleanser, toothpaste, shampoo, shower gel and so on. In our daily life, the use of tea polyphenols is still very extensive.
To sum up, tea polyphenols are a large family in which different substances play different active roles. However, from the perspective of tea tasting, it is not that the more polyphenols, the better, but to pay attention to the appropriate proportion.
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